ABR as defined in the ATM Forum standard provides a flow control mechanism intended for non-real time traffic. Implementation of ABR within the network could lead to an efficient utilization of network resources. UBR service, on the other hand, provides a non-controlled flow of non-real time data through the network in a "best effort" mode. For instance, if congestion occurs at some middle switch which causes ATM cells or ATM packets to be dropped at the middle stage switch, then the utilization of these subsequently dropped cells or packets in the preceding switches is wasted. The present invention relates to the mapping of UBR services to ABR service at the edge of the network in order to provide a flow control mechanism for UBR traffic thus yielding an efficient utilization of the network resource. Let the mechanism that maps UBR to ABR to be named as UBR-ABR gateway.
Mapping of UBR traffic to ABR traffic allows an efficient utilization of the network resources. Although ABR services is provided in the forthcoming switches, many adaptor cards and uplink cards at the edge of the network do not have ABR functionality. These hosts at the edge of the network have no choice but to use ABR service for their non-real time data traffic. UBR-ABR gateway, as disclosed, would get the best features of ABR service for UBR traffic generated at the edge of the network. End hosts are not aware of such gateway and they would definitely notice better performance in terms of cell loss and delay.